Geometry compression is the coding of 3D geometric data in a form that requires less space to store and less bandwidth to transmit. Animated geometry compression is the compression of temporal sequences of geometric data. An octree-based motion representation method in which a small set of motion vectors are generated for each frame by analyzing the motion between consecutive frames was proposed in a previous research. The recursive dividing of regions by the algorithm may put vertices with the similar motions into multiple disjoint regions of various depths and sizes. This paper proposes a method that enables the sharing of motion vectors in different regions. The cost of storing the reference to another motion vector is much lower than the cost of storing the whole motion vector. We implemented the motion vector sharing algorithm and compared the performance of this method to the original method on four animation sequences: dance, chef, chicken and cow. The improvement in compression ratio of P-frames ranges from 11% to 52%.